The stability of polymorphs of MgCl2 - An ab initio study

Periodic Hartree-Fock calculations show that the layered structures of α- and β-MgCl2 are stable at the HF level; earlier work has suggested this was not so for β-MgCl2. The neglect of correlation leads to a large overestimate of the Cl-Cl interlayer separation and hence of the c lattice parameter....

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Publicado: 1997
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00092614_v278_n4-6_p267_Barrera
http://hdl.handle.net/20.500.12110/paper_00092614_v278_n4-6_p267_Barrera
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_00092614_v278_n4-6_p267_Barrera
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spelling paper:paper_00092614_v278_n4-6_p267_Barrera2023-06-08T14:33:43Z The stability of polymorphs of MgCl2 - An ab initio study Periodic Hartree-Fock calculations show that the layered structures of α- and β-MgCl2 are stable at the HF level; earlier work has suggested this was not so for β-MgCl2. The neglect of correlation leads to a large overestimate of the Cl-Cl interlayer separation and hence of the c lattice parameter. Structures optimised using density functional theory and the same basis set are in better agreement with experiment, α- and β-MgCl2 are close in energy at HF and DFT levels, and vibrational effects are likely to be important in determining their relative stability. Neglecting possible distorted variants of the more ionic rutile and fluorite structures, we estimate transition pressures of ∼ 17 GPa for β-MgCl2 → rutile and ∼ 77 GPa for rutile → fluorite. © 1997 Elsevier Science B.V. 1997 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00092614_v278_n4-6_p267_Barrera http://hdl.handle.net/20.500.12110/paper_00092614_v278_n4-6_p267_Barrera
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description Periodic Hartree-Fock calculations show that the layered structures of α- and β-MgCl2 are stable at the HF level; earlier work has suggested this was not so for β-MgCl2. The neglect of correlation leads to a large overestimate of the Cl-Cl interlayer separation and hence of the c lattice parameter. Structures optimised using density functional theory and the same basis set are in better agreement with experiment, α- and β-MgCl2 are close in energy at HF and DFT levels, and vibrational effects are likely to be important in determining their relative stability. Neglecting possible distorted variants of the more ionic rutile and fluorite structures, we estimate transition pressures of ∼ 17 GPa for β-MgCl2 → rutile and ∼ 77 GPa for rutile → fluorite. © 1997 Elsevier Science B.V.
title The stability of polymorphs of MgCl2 - An ab initio study
spellingShingle The stability of polymorphs of MgCl2 - An ab initio study
title_short The stability of polymorphs of MgCl2 - An ab initio study
title_full The stability of polymorphs of MgCl2 - An ab initio study
title_fullStr The stability of polymorphs of MgCl2 - An ab initio study
title_full_unstemmed The stability of polymorphs of MgCl2 - An ab initio study
title_sort stability of polymorphs of mgcl2 - an ab initio study
publishDate 1997
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00092614_v278_n4-6_p267_Barrera
http://hdl.handle.net/20.500.12110/paper_00092614_v278_n4-6_p267_Barrera
_version_ 1768546283526553600

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